OBSERVATIONS OF LUMINOUS METEORS. ] 59 



Lacerta, on August 14th; Mr. Clark recorded on that date seven Perseids and 

 five meteors from other radiant-points in three quarters of an hour ; on the 

 16th, Mr. Clark saw 3 Draconids in half an hour, and Mr. Denning noted two 

 Perseids between 10 h and ll h p.m. 



Resuming observations during the same periods in the present year, Mr. 

 Denning noted numerous meteors in July and August, 1877 (' Nature ' July 

 27th and Aug. 9th, 1877, vol. xvi. pp. 286, 362), with a similar but more 

 complete list of the radiant-points which were most conspicuous in the middle 

 of July ; and among them certain radiants in Cassiopeia and Perseus were very 

 active. These latter correspond approximately in epoch and position to the 

 theoretical radiant-points of the comets of a.d. 770 and 1764, and they ap- 

 pear to be distinct from the true Terseus shower, the first member of which, 

 Mr. Denning states, was not visible until the morning of July 29th, nor any 

 perceptible abundance of them until the 5th of August. During the later 

 period of the first ten days of August, 1877, Mr. Denning recorded 229 meteors 

 unconformable to Perseus, among which a radiant in Cassiopeia was again an 

 active and conspicuous centre of divergence. It thus becomes important to 

 trace in future the exact places and durations of these Cassiopeiad showers, 

 and to fix their dates of maximum abundance, so as to distinguish them com- 

 pletely from the Persei'd shower with which they have probably been confused, 

 and from whose diffuse region of scattered radiation it will perhaps be possible 

 hereafter to separate their meteors. 



Principal radiant-points ob- 



4° +35° w Andromeda;; 21 meteors, 

 served at Bristol (W. R , fi +53 a Cassiopeia; ; 11 meteors. 

 Denning), July 6-20, 1S77 j 47 +45 a, (3 Persei ; 5 meteors = $ 1764, ® (?). 



(197 meteors seen). | 3(5 +47 Persei ; 6 meteors =$ 770, ??(?). 



I, (and 15 other showers, in Aquarius, Cygnus, Pegasus, &o.) 

 /"333°+46°. Lacertids. 

 Ditto, Aug. 3-10, 1877 (229 j 10 +38 Greg, key map, 1875-76, Nos. 100 and 132. 

 meteors unconformable to J 30 +36 ,, „ No. 98. 



Perseus, in a total watch j 70 +65 A new shower, well marked on the 7th and 10th. 

 of 15 h 30™). | 315 +51 Cvgnids. 



^ 6 +53 Cassiopeids, Greg, 1875-76, No. 98. 



Between the 9th and 12th of August, 1876, there were mapped 115 meteor- 

 tracks (by Messrs. Backhouse, Clark, Denning, Herschel, Lucas, and Wood) 

 unconformable to the Perseus radiant region, a preliminary reduction of which 

 was made to assign their radiant-points. No less than seventeen distinct 

 centres of divergence are recognizable in the collection, only the numbers of 

 the meteor-tracks belonging to whose different systems can here be recorded, as 

 they are in general too few to allow positions of any important accuracy to 

 be derived from them ; and further corroborations of these meteor-systems 

 contemporaneous with the Perseus shower will be required to define their real 

 centres with precision. 



Liar 9-19 1876' [Cassiopeia. « Draconis. aPegasi. Honores. SAquarii. Musca. /3Aurig&\ UrsaMaj. 



SSTitSn.} 16 13 10 9 8 8 8 7 



Polaris, j; Draconis. r\ Hcrculis. y Pegasi. /^Aquarii. Delphinus. Cygnus. 

 6 5 5 5 5 4 3 



One or two meteors with short tracks also indicated radiant-points near 5 

 Vulpeculse or Serpentis and i Ophiuchi ; five or six Pegasids were derived 

 by Mr. Clark from each two points at 337", + 25°, and 355°, +18°; aud on 



